Dental Fluorosis & Thyroid Dysfunction
Floyd DeEd's pioneering research on thyroid dysfunction and "mottled teeth"
In 1940, DeEds and Robert Wilson reported dental fluorosis in rats to be the result of the synergistic action of fluoride and thyroid hormones. Results were described as "strikingly clearcut" (Wilson & DeEds, 1940).
Floyd DeEds was head of the Pharmacology Laboratory of the U. S. Department of Agriculture (then under the FDA), and in 1933, had conducted the first-ever review of chronic fluoride poisoning (DeEds, 1933).
DeEds and Wilson were faced with the dilemma of setting a spray residue limit for fluoride in pesticide applications. They were bewildered by the results of their experiments and wrote:
“In regions where only a few indigenous individuals have mottled enamel, are those few the individuals who were hyperthyroid during the period of enamel formation? Should a spray residue tolerance limit for fluorine be set to protect the normal, the hyperthyroid, or the hypothyroid individual? Lastly should the tolerance limit take into consideration that in certain areas the public is already exposed to a fluorine intake in the drinking water?”
Later in the same year, DeEds conducted further experiments with TSH, the thyroid-stimulating hormone, and reported that TSH also increased bleaching of the incisors (dental fluorosis) in rats (DeEds et al, 1940).
In 1941, DeEds summarized his findings in the journal of the American Dental Association (DeEds, 1941):
“Administration of thyroid greatly enhances the susceptibility to fluorine poisoning...Administration of the thyrotropic hormone secreted by the anterior pituitary gland increases susceptibility to fluorine toxicity...Variations in the activity of the thyroid and pituitary glands may be factors in the individual variation in susceptibility to fluorine toxicity."
In 1951, DeEds and colleagues contributed a report for the USDA’s 1950-1951 Yearbook of Agriculture. The book was distributed widely in the US at the time of the Delaney Hearings.
DeEds et al. wrote:
“…pharmacologists learned that the susceptibility to fluorine toxicity was increased by raising the metabolic rate. The increase in metabolism was induced either by feeding desiccated thyroid or by injecting the thyrotropic hormone of the pituitary gland. The practical significance of the discovery is in its bearing on the public health hazard of fluorine, whether it be in spray residues or in drinking water.”
Incredibly, in 1975, in a public press release denying that fluoride causes the delayed eruption of teeth, the US PHS Division of Dentistry claimed that none of the published work of DeEds referred to fluoride as affecting thyroid function (US PHS, 1975).
Knowledge in 2022
Although it has been established for over 100 years that dental fluorosis is closely tied to thyroid dysfunction, the field of dentistry claims that the mechanisms leading to dental fluorosis are still not known and that the condition is a “cosmetic” defect only.
REFERENCES:
DeEds F - "Chronic Fluorine Intoxication. A Review" Medicine 12:1-60 (1933)
https://agris.fao.org/agris-search/search.do?recordID=US201300669410
DeEds F - "Factors in the Etiology of Mottled Enamel" The Journal of the American Dental Association 28(11):1804–1814 (1941)
De Eds F, Wilson RH, Cutting WC - "Thyrotropic hormone and fluorine activity" Endocrinology 26(6):1053-1056 (1940)
DeEds F, Wilson RH, Ambrose A – “Hazards and Potential Drugs” in: Crops in Peace and War, The Yearbook of Agriculture 1950-1951, US Department of Agriculture, Washington, D.C. (1951)
US Department of Health, Education, and Welfare, Public Health Service, Health Resources Administration, Division of Dentistry - “Use of optimally fluoridated water does not delay tooth eruption” (FL-79, 1975)
Wilson RH, DeEds F - "The Synergistic Action Of Thyroid On Fluoride Toxicity" Endocrinology 26:851 (1940)
https://academic.oup.com/endo/article-abstract/26/5/851/2772876